Amazing site: On-Line Encyclopedia of Integer Sequences® (OEIS®) Wiki

http://oeis.org/
Majed A.
majedline.blogspot.com

Google Master Search terms

-- Search on specific site
site: websiteNameHere yourTextHere
-- Related word; Synonyms
~yourTextHere
-- Exact words
"yourWordHere"
-- Exclude term
-yourWordHere
-- Between two dates
2008..2010 yourTextHere
-- File type search
filetype:PDF yourTextHere
-- Show results with the word in title
intitle:yourTextHere
-- * Will be replaced with other words common with the searched term
*yourTextHere
yourTextHere*PartTextHere*OtherPartTextHere
-- Search for papers with specific author
author:AutherNameHere
-- Definition
define: yourWordHere
-- Calculator
2*2
(3/2)*100
-- Unit converter
10 KM in Miles
-- research, use: http://www.jstor.org/

Floating-point errors. They cannot precisely represent all real numbers. Here is an example.

"Floating-point numbers cannot precisely represent all real numbers, and that floating-point operations cannot precisely represent true arithmetic operations, leads to many surprising situations. This is related to the finite precision with which computers generally represent numbers." (From Wiki)

Read more about my example here.
http://majedline.blogspot.ca/2012/06/floating-point-errors-they-cannot.html 

Online Compilers

Two cool online compilers for code snippets:
http://codepad.org and http://ideone.com

I tried this C++ Fibonacci function and the compiler worked:

#include <iostream>
 
int fib(int n)
{
     if ( n == 0 ) return 0;
     if ( n == 1 ) return 1;
 
     return fib(n-1) + fib(n-2);
}
 
int main(){
 printf("Fib Val: %i", fib(7));
 return 0;
}

.NET C# Get Byte array from a file

public static byte[] GetBytesFromFile(string file)

{

try

{

// check if this is a file name;

if (file == null)

return null;

if (file.Trim().Length == 0)

return null;

// get the size of the buffer

int bufferSize = (int)(new System.IO.FileInfo(file).Length);

// check if the file has anything.

if (bufferSize == 0)

return null;

// create the buffer with the proper size

byte[] buffer = new byte[bufferSize];

// create the stream

System.IO.FileStream fs =  new System.IO.FileStream(file, System.IO.FileMode.Open);

// create the reader of the stream

System.IO.BinaryReader reader = new System.IO.BinaryReader(fs);

// populate the buffer

buffer = reader.ReadBytes(bufferSize);

// Close the stream

fs.Close();

fs.Dispose();

// close the reader

reader.Close();

fs.Dispose();

return buffer;

}

catch (Exception ex)

{

System.Windows.Forms.MessageBox.Show("Please Make sure that the file is valid or is not in use. Details:\r\n" + ex.Message);

return null;

}

}

.NET C# Create a file and open it using Default Application Type

public static void OpenFileWithDefaultApplication(string fullfileLocationAndName, byte[] data)

{

try

{

System.IO.FileStream fs =   new System.IO.FileStream(fullfileLocationAndName, System.IO.FileMode.Create, System.IO.FileAccess.ReadWrite);

fs.Write(data, 0, data.Length - 1);

fs.Close();

fs.Dispose();

System.Diagnostics.Process.Start(fullfileLocationAndName);

}

catch (Exception ex)

{

MessageBox.Show("There was an error opening the file: " + ex.Message);

}

}

JAVA Write to a file

// Write x to file
public void writeFile(String x, String file){
    try{
        // Create file
        FileWriter fstream = new FileWriter(file);
        // Create Writer
        BufferedWriter out = new BufferedWriter(fstream);
        // Write x to the file        
        out.write(x);
        //Close the output stream
        out.close();
    }catch (Exception e){
        //Catch exception if any
        System.err.println("Error: " + e.getMessage());
    }
}

JAVA Date and time formatting

public static String getDateNow(){
  DateFormat dateFormat = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss");
Date date = new Date();
return (dateFormat.format(date))+"";
}

JAVA Manipulate a String using regular expressions

// Example 1, remove all instances of a word with another in a String.

// Example 2, remove all white spaces from a String

public static String manipulateString(String s){

  String result = s;

  

  //1 replace all instances of the word foo with the word bee 

  result = result.replaceAll("(?:foo)", "bee");

  // remove all white space

  result = result.replaceAll("\\s+", "");

   

  return result;

}

JAVA Open a file using the default application editor.

// Example Foo.xls will be opened with Excel
// Make sure to import the class java.awt.Desktop

public static void OpenFile(String filename){
  try{
    // Check if class 'Desktop' is supported on the platform 
    if (Desktop.isDesktopSupported()) {
      Desktop.getDesktop().open(new File(filename));
    }else{
      System.out.println("Class Desktop is unsupported");
    }
  } catch (Exception ex){
    System.out.println("Error opening "+ filename);
  }
}

.NET C# Write to a file

public static bool WriteToFile(string fileName, string fileContent)
{
    fileName = fileName;
    System.IO.TextWriter tw;
    try
    {
        tw = new System.IO.StreamWriter(fileName, true);
        tw.WriteLine(fileContent);
        tw.Close();
        return true;
    }
    catch{}
    return false;
} 

.NET C# Read from a file

public static string ReadFromFile(string fileName)
{
    string ret = "";
    System.IO.StreamReader sr;
    try
    {
        sr = new System.IO.StreamReader(fileName);           
        ret = sr.ReadToEnd();
        sr.Close();
        return ret;
    }
    catch{ return null; }
}